1. Field of the Invention
This invention relates to a pressure-adjusting reservoir and especially to a pressure-adjusting reservoir for ABS (Antilock Brake System) suitable for vehicle ABS control, and a vehicle brake device using the same.
2. Related Art
Conventional vehicle brake device for performing an ABS control using a pressure-adjusting reservoir (switch reservoir) is disclosed in Japanese patent application Laid-open No. Hei. 6-8810.
FIG. 11 shows the pressure-adjusting reservoir 200 according to a related art. The vehicle brake device using the pressure-adjusting reservoir 200 is capable of adjusting a high master cylinder pressure by a pressure-adjusting valve 201 provided to the pressure-adjusting reservoir 200. That is, the pressure-reservoir is constructed so as to prevent the high master cylinder pressure from being applied to a sucking port of a pump even if an amount of brake fluid becomes full in the pressure-adjusting reservoir, when the brake fluid in the pressure-adjusting reservoir 200 is sucked by the pump.
FIG. 12 is an enlarged partial view of the pressure-adjusting valve 201 of the pressure-adjusting reservoir 200. FIG. 12 shows a condition that the pump is operated when a brake pedal is depressed. The pressure-adjusting valve 201 will be concretely explained with reference to this figure.
The pressure-adjusting valve 201 is constructed by a ball valve 202, a valve seat 203, and a pin 205 interlocked with a reservoir piston 204 (see FIG. 11). When the pressure-adjusting reservoir 200 has an enough space into which the brake fluid flows and the ball valve 202 is separated from the valve seat 203 by the pin 205, the pressure-adjusting valve 201 allows the brake fluid to flow to the pressure-adjusting reservoir 200 through a gap between the ball valve 202 and the valve seat 203. On the contrary, when the pressure-adjusting reservoir 200 has not enough space into which the brake fluid flows, the ball valve 202 contacts with the valve seat 203 so that the pressure-adjusting valve 201 stops the brake fluid flowing to the pressure-adjusting reservoir 200.
However, as shown in this figure, the pin 205 of the conventional pressure-adjusting reservoir 200 is formed so that a seat face 205a contacting with the ball valve 202 is perpendicular to an axis of the pin 205. Therefore, the ball valve 202 may unstably move and this movement may cause a pulse of the brake fluid pressure or the like.
Especially, when the ball valve 202 is pushed up toward the pin 205 by a spring 206, the unstable movement of the ball valve 202 becomes remarkable by an action of a spring force and a fluid force applied to the ball valve 202.